If we want to do positioning, the only choices are to add "class=xxx" and/or "style=xxx" as options in addition to "width=nn" and "height=nn" that are already recognized in the 3rd part of the transclusion syntax..

Suggest we add both class and style.

A problem related to positioning is transclusion wrapping. Some or all of the styles or classes applied to the img or object must be moved or copied to the wrapper. In particular, 'style="float: right;"' must be copied/moved to the wrapper.